Process for the preparation of ethylene-butadiene copolymers

ABSTRACT

Ethylene and butadiene are copolymerized in the presence of a ternary catalyst system consisting of: (a) vanadium or vanadyl chloride; (b) an aluminum compound represented by the formula: Al RxX3 x, wherein R is alkyl, aryl, alicyclic or hydrogen, X is a halogen and 1 &lt; OR = X &lt; OR = 2; and (c) is an aluminum compound containing aluminum-nitrogen bonds, such as aluminum tris-dialkyl amide.

United States Patent n 1 Cucinella et al.

[ Aug. 26, 1975 PROCESS FOR THE PREPARATION OF ETHYLENE-BUTADIENE COPOLYMERS [75] Inventors: Salvatore Cucinella; Alessandro Mazzei, both of San Donato Milanese, Italy [73] Assignee: Snam Progetti S.p.A., San Donato Milanese, Italy [22] Filed: Dec. 14,1973

[2|] App]. No.: 424,718

[30] Foreign Application Priority Data Dec. 20, 1972 Italy 33277/72 Oct. 16. 1973 Italy 30155/73 [52] US. Cl. 260/853 R; 260/949 E [51] Int. Cl. C08d 3/06; C08f 15/04 [58] Field of Search 260/853 R. 94.9 E

[56] References Cited UNITED STATES PATENTS 9/1964 .Iuvcland et al. 260/853 R 6/1968 Marconi et a1 t. 260/949 CA 1/1971 Delbouille et al 260/853 R Primary Examiner1oseph L. Schofer Assistant ExaminerA. Holler Attorney, Agent, or Firm-Ralph M. Watson, Esq.

[57] ABSTRACT Ethylene and butadiene are copolymerized in the presence of a ternary catalyst system consisting of: (a) vanadium or vanadyl chloride; (b) an aluminum compound represented by the formula: AI R ,X wherein R is alkyl, aryl, alicyclic or hydrogen, X is a halogen and l s X s 2; and (c) is an aluminum compound containing aluminum-nitrogen bonds, such as aluminum tris-dialkyl amide.

7 Claims, No Drawings PROCESS FOR THE PREPARATION OF ETHYLENE-BUTADIENE COPOLYMERS The present invention relates to a process for the preparation of ethylene-butadiene copolymers by means of ternary catalysts constituted of vanadium halides. aluminum compounds containing aluminumnitrogen bonds and aluminum alkyl-halides.

It is known that systems of the Ziegler type are not suitable for such a copolymerization because of the fact that mixtures of two homopolymers or very low molec ular weight copolymers are obtained, which show an insufficiently homogeneous composition or an unsaturation distribution which does not allow an effective cross-linking with sulphur,

It is also known that polyethylene, when it is crosslinked, shows significant improvements in its chemicalphysical properties which allow a wider use thereof.

Those skilled in the art know that cross-linking improves the crazing strength under load in the presence of surface active agents, the impact and heat strength of the manufactured articles.

Furthermore cross-linking is useful in order to obtain foamed materials at very low density, thermoshrinkable films, etc. The processes, which are usually employed for cross-linking polyethylene, are based on the use of penetrating radiations or of organic peroxides.

However the first process requires very expensive ap' paratus whereas the second one has the disadvantages due to the employment of very reactive substances which, moreover, have a difficultly controllable decomposition kinetic.

The difficulties associated with polyethylene cross' linking may be overcome by employing the copolymers which are the subject of the present invention, which may be cross-linked by sulphur and accelerator systems that have been employed in the vulcanization of the usual elastomers.

In this case the cross-linking process is easily controllable and can be adapted to a convenient technology.

The process of the present invention makes it possible to obtain copolymers having high molecular weight, high crystallinity of the polyethylene type with low butadiene content and which are crosslinkable by vulcanization with sulphur base recipes, through catalysts constituted by:

a. vanadium or vanadyl halide-derivatives;

b. an aluminum compound of the AIR X type wherein R is an alkyl. aryl or cycloalkyl radical or a hydrogen atom. X is a halogen and l X 2',

an aluminum compound containing aluminumnitrogen bonds selected from the following ones:

- aluminum-triamides having the general formula Al(NR wherein R has the aforesaid meaning; AlH,( NR wherein R and x have the aforesaid meanings;

aluminum polymeric compounds having the formula wherein R is a hydrocarbon radical selected from the aforementioned ones. X may be hydrogen or halogen; the halogen atom number may be or is lower than n, the balance to n being constituted by hydrogen atoms, n is from 2 to 50 and preferably from 3 to [2. The components of the catalytic system are employed at an Al-N containing compound/vanadium compound ratio higher than 0.l whereas the ratio between the aluminum alkyl-halide moles and the vanadium moles is higher than 05 The best results are obtained when the molar ratio between the AlN containing compound and the vanadium compound ranges from 0.5 to 3 whereas the ratio between the aluminum alkyl-halide derivative and the vanadium compound ranges from 2 to [2.

The catalyst may be preformed or prepared in the presence of both monomers. The copolymerization is carried out in the presence ofa solvent which may consist of an aliphatic, aromatic or alicyclic hydrocarbon, at a pressure ranging from i to I50 Kg/cm due to ethylene and to hydrogen eventually fed as molecular weight regulator.

The reaction temperature ranges from 30 to +150C.

At the end of the reaction the copolymer may be recovered according to usual methods, by removing the solvent and drying in the presence of suitable antioxidants. The monomers may be introduced together, at the wanted ratios, at the beginning of the reaction; however it is advantageously added before the fixed bu tadiene amount and then to send ethylene at a constant pressure for all the wanted polymerization time. or to feed such a monomers mixture that the composition in the polymerization reactor shall be constant during the course of the polymerization. It is preferable that the catalyst components be mixed in the presence of both monomers.

According to the starting mixture of monomers, copolymers are obtained containing butadiene in amounts ranging from 0.1 to

The butadiene units in the copolymer are in the L4 trans configuration, or partially show an l,2 configuration close to the 1.4 trans one, this latter being however the prevailing one.

When no use is made of regulating agents, the copolymer molecular weights are usually high and, therefore, the intrinsic viscosity, determined in decaline at I35C, may vary up to [0; by changing the copolymerization conditions it is possible to regulate the molecular weight also to viscosity values lower than 1.

Generally the obtained copolymers are completely soluble in hydrocarbon solvents having a boiling point near to the polyethylene melting point, according to the absence of gel before the sulphur base vulcanization.

The composition of the copolymers containing up to 20% butadiene by moles is generally calculated from calibration curves obtained by correlating NMR analysis results and IR band intensities. Particular use is made of relations between the content of trans 1,4 butadiene unities and the values of the ratios D1035). 13.90 D1035. 2,aop. reported in "Chimica e lndustria 53 (1971).

The D IO is moreover measured for dcter mining the butadiene unities in 1,2 configuration.

When studying copolymers having a butadiene amount equal to or higher than 20% by moles, use is made of the direct NMR analysis.

The X-ray examination of the copolymers at high ethylene content 95%) shows the presence of crystallinity of polyethylene type higher than'70% while there is no crystallinity attributable to butadiene sequences.

The cross-linking of the ethylcne-butadiene copoly mers. which easily occurs also on products having a low 4 The polymerization started at once. as emphasized by a gradual increase in the temperature of about 8C; having reached the value of 25C after about minutes from the start of the reaction. the temperature butadicne content 6 107: by moles). is measured by slowly fell again to [7C. the gel percentage caused by the vulcanization. During the polymerization run the autoclave pressure The gel percentage is determined by subjecting the was maintained constant by a connection to the ethylcopolymer. before and after the vulcanization, to a ene feed cylinder. After 1 hour the gas was rapidly discontinuous extraction with boiling xylene in a charged and 20 cc of a toluene solution at 30% piperi- Kumagawa extractor. 10 dine. to which an antioxidant had been added. were The low butadiene content copolymers. besides havadded to the polymerization mixture followed by an exing unchanged the peculiar and good properties of cess of methyl alcohol. The copolymer was recovered polyethylene homopolymer after cross-linking with sulby filtering the suspension. washed by an alcohol to phur. contemporaneously show a higher thermal resiswhich an antioxidant had been added and dried at 50C tance. l5 under vacuum. The yield was 54 grams. The [17] value.

Also the crazing under load strength increases in the determined at 135C in decalinc was 3.6. The IR. analpresence of surface active agent. and also the impact ysis showed that the D lD ratio was 0.36; resistance. D means the optical density of an absorption The so obtained copolymers are of peculiar imporband typical of L4 trans enchainment ofbutadienc poltance in fields wherein use is now made of more expen- 20 ymeric unities. whereas D means the optical sive materials, such as the coating of cables for special density of a band typical of polymethylene sequences: uses. pipes for hot liquids, and generally materials havthe absorptions of butadiene enchainment of vinyl type ing a particular resistance to solvents or vapours at high were insignificant. The X-ray examination showed a temperature. in the automotive industry and others. crustallinity of 82%. The copolymer was cross-linkable Moreover these copolymers can be employed for the with sulphur as it resulted from continuous extraction production of difunctional ethylene oligomers by utiliztests performed with boiling xylene in a Kurnagawa exing oxidative reactions which, by etching the double tractor, which were carried out respectively on a cobond. may give rise to oligomers having oxygen conpolymer sample as such and on a copolymer sample taining functions as end groups. Such oligomers may be previously treated with a sulphur base recipe. in the employed for polycondensation reaction or other purfirst case the product was entirely extractable. while in poses. the second one. 8971 of the product was insoluble. The The following examples illustrate the invention. but sulphur treatment consisted of a pressing at 180C for they are not limitative thereof. half an hour according to the following recipe:

EXAMPLE I Copolymer I00 Use was made of a stainless steel autoclave having l m g 3246 l l ca acit e ui d with an ancho ma netic stirrer zmc 5 P 5" q P f g Stearic Acid l and held at 17C by a liquid circulating through the ex- Nous special 2.5 ternal cooling jacket. from which air was removed; DM therein a solution of ml 400 of toluene containing 1 4o mmole of VOCl and 1 mmole of Al(NMe was introu duced (the two components were previously added as T0 l" P p Compansom Sample which was aforesaid and reacted for 5 minutes at room temperal m the sulphur f was P for wre) 4 g of butadiene and Kglcma of H2 were the" half an hour at 180C before being extracted wlth x introduced into the autoclave. it was saturated with lensethylene to 25.5 Kg/cm and finally 8 mmoles of EXAMPLES 243 AlEtCl were introduced. dissolved in 20 ml of toluene. by means of an ethylene pressure regulated at 26 Y wfnkmg accordmg P example same (mpoly' kg/cmz merlzation tests were carried out.

The conditions and the results are reported in table I.

TABLE I Catalyst Cocatalyst (opolymer RX '4 Ere Boilamen Re- Reing Crisacac- LR. l-lx- Xitaltion H2 Tollion Examen l35C tract lcne lin- Ex. vcs- Mono- Kg/ uene time Yield I'nl NT. 1' ity No. scl mers cm ml Type mmoles Type mmoles T( (mini 1; D dec. ('1 l) 1 2 Autohut. I8 600 v0 AlFts l7+20 so 25 0.42 319 1.2 79 so clave 1; l5 (ls l (l ht. Cl. a Al 2 rlu cm 3 Autobut. I0 400 v0 l Allitu l7+3l an 32.5 0.2l nd 24 3.1.6 n.d.

clavc g It] ("I (i ll. cl. 8 1 Kg/ cm 4 Allin hut. :2 400 \'o l All-.1 m n+3 so 34 um I 4: a u "a.

TABLE l-continued Catalyst Cocatalyst Copolymer RX 96 Ex- Boilamen Re- Reing Crisacac- [.R. Ex- Xitaltion H Toltion Examen 135C tract lene Iin Ex. ves Mono- Kg/ uene time Yield D [1,] NT. T ity No. sel mcrs crn ml Type mmoles Type mmoles TC tmin.) g B dec. (*"l ii clavc g 5 Cl Cl lt ct. 8 Al 1 Kg/ tNMe t,

em- 5 Autobut. 22 400 V0 l AlEtl0 l7+3'-) (d0 45 0,09 L87 0.l 3.4 n.d.

chive g 5 Cl; (L33 (I It, et. 8 Al I Kg] t mt cm 6 Autobut, "2 400 V() l AlEtl0 l6+20 60 42 0 "8 2.54 0.3 72 n,d.

clave g 5 Cl I (I lt. et 8 Al 1 Kg] m cm 7 Autobut. 2'. 400 V0 l AlEtl2 I6 60 I45 (L24 3.06 0.2 73 n.d.

clave g 5 (l 3 (l It. et. 8 Al I Kg/ M -nl em- 8 Autobut. I0 400 V 1.5 AlEt- 4.5 ltH-l'l 22,7 0."'l BIS 0 l5 n.d.

clave g l() Cl (I lt et. 8 l Kg/ cm 9 Autnhut. i0 400 V l AlEl- 3 l7+l9 b0 6 0.75 in]. n.d.

clan: g Cl Cl ll. et. K I Kgf cm l0 Autobut. 10 400 V L5 AlEt- 4.5 lt'w-l-ZS 20.8 0 Z5 2.8) 0 68 ".Ll

clan: g It) Cl. 1 (l lt. ct. l8 Al I Kg! tNMtr.

cm ll Allluhut. Jill] \v l.$ AlEi- 4.5 l7+28 (ill 0.3) 3.6] (I 82 time g 20 (I l (l It. ct. IX Al I Kg/ lNMecm I: Autohut. l3 I200 .l Alli! "(+20 60 -13 [L62 l.'-)) 0 7i H5 clan: g 20 fl, 3 (l It. et. K5 Al 2 Kg," tNMe L.

cm 13 Auto but 400 V 1.5 Allit- 4.5 l9+2l 60 37 L04 9.67 0.3 57 85 clme g 20 Cl, 1 ('I- ll.. Lt. H4 Al 2 Kg/ (NMt- N I tl It as not treated h sulphur ham: recipes I I" I It was treated by sulphur hast: recipes ltd It as nu! delernnned By examining examples 4. 5 and 6 it is possible to note that. the other conditions being the same, the addition of increasing amounts of aluminum triamide to the OVCL AlEtCl mixture produces a butadiene increase in the resulting copolymer, products being obtained which are crossdinkable with sulphur.

On the other hand the comparison between two copolymers having almost the same composition. respectively obtained without or with aluminum triamide, emphasizes that the former copolymer shows a crosslinking before the sulphur base treatment (partial soluhility at boiling xylene extraction. ex. 3) and then it is little cross-linked by sulphur whereas the latter one (ex. 6) is completely soluble at boiling xylene extraction, in spite of a little increase of the butadiene content and has 72% gel after the treatment with sulphur base recipes.

By comparing the example 8 with the example [0 it will be noted that. when use is made of VCl base sys- EXAMPLES l4-l7 According to what has been pointed out above. copolymerizations were carried out with higher butadicne amounts.

In such a way it is possible to obtain copolymers having a prevailing butadiene content.

The working conditions and the results are reported in table 2.

TABLE 2 Ex. H Toluene Temp. Butadiene No, Vessel Monomers Kg/crn ml Catalyst catalyst Time Yield A h moles l4 Autoclave BTD g l2 I6 400 OVCL, mmole l AIEtCl l6+ll l h 25.5 20V) It. I Etilene AltNMe h mmole I mmoles '9 Kg/cm 8 l5 Autoclave BTD g 24 lo 400 idem idem lo I h 2" 4m") It. I Etilene Kg/em 8 l6 Autoclave BTD g 32 400 idem idem l6 1 h 23.5 h7t) It. 1 l-Itilene Kg/cm" 8 l7 Autoclave BTD g l2 I6 400 idem idem l6+llt l h "5 8.9

It. I Etilene Kg/cm 8 t'lDeterminetl by NMR way,

EXAMPLES l8-25 Use was made of a stainless steel autoclave having I the analysis and the vulcanization thereof were carried out as in the first example.

The results are reported in table 3.

Test

AIR, (NR [Autoclave l l toluene ml 400; (1 H, 8 Kg/cm. H 22 Kg/em". butadiene g 5; time 60'] Catalyst TC Polymers OVCl Amminoalane AIEtCl, g LR. analysis I") "/1 gelt **l mmoles mmoles Dunn /D |1y| N.V. V,

Type mmoles I8 I 8 164-33 42.5 0.064 1.77 t) 0 I) l AlH(NMe h), 0.5 8 l6+30 47 0.1 l 2.34 ().l 6 20 l AlHlNMeM), l 8 l6+20 37 0.21 3.73 0.l 4t 2l 1 AlHtNMeh): 1.5 8 16+ 23 45 0.37 3.15 0.2 33 22 l AlH(NMe),), 2 8 l6+22 46 0.33 4.70 it does not melt 23 l AlHtNMel 3 8 l6+l7 20 0.46 3.24 it does not melt 24 l AlHlNMBlzlz l 0 l6 0 25 l AlH,NMe, 2 8 l6 5 0.34 3.49

l) Determination in decaline at lC t )Cross-ltnking tests by sulphur base recipes: N.\/. before the treatment: V after the treatment EXAMPLES 26-28 According to the preceding examples three copolymerization tests were carried out by letting aminoalane be replaced by polyiminoalane. The conditions and the results are reported in table 4.

TABLE 4 Ethylene-butadiene copolymerization tests by the ternary catalyst systems: OVCL,AlfitCl -Polyiminoalane (PIA) (the other experimental conditions were equal to the one of table 3) Catalyst TC Polymers Tests OVCl PIACI AlEtCl g LR. Analysis' Z gel mmoles mmoles mmoles Dubai in] N. V.

16 l l 8 l6 39 5S 0.] L99 1 7.4 27 l 2 8 l6 25 47 0.27 .11. I83 4l .6 28 l 3 8 l6 l6 0.4 3.20 0.8 557 "Determination in deealin: at I35C "MI was not determined because of the gel presence Truss-linking tests by sulphur base recipes: N. untreated polymer; V treated polymer 'PlACl means a poly N. isopropyliminoalane containing chlorine atomsthe chemical analysis thereof showed N/Al U'Jltv H activelAl 0.97. (l/Al [Lin two components were previous added as aforesaid and reacted for 5 minutes at room temperature).

Then 5 g of butadiene and 22 Kg/cm of H were in trodueed into the autoclave.

An ethylene stream was then fed up to a pressure slightly lower than that of saturation and, finally. 8 mmoles of AlEtCl were introduced, after having been dissolved in 20 ml. of toluene. by an ethylene pressure. The polymerization started at once as shown by a gradual increase of the temperature, which then slowly lowered to the starting value. The recovery of the polymer.

What we claim is:

1. Process for the preparation of ethylene-butadiene copolymers containing from 0.1 to by moles of butadiene units, wherein the polymerization reaction is carried out in the presence of a ternary catalyst system consisting essentially of a. vanadium or vanadyl chloride h. an aluminum compound represented by the formula AIR X wherein R is alkyl, aryl, alicyelic or hydrogen, X is a halogen and l s X 4 2. and

mula

Al-N l l wherein R is a hydrocarbon radical selected from the aforementioned ones, X is hydrogen or halogen; the halogen atom number is or is lower than n. the balance to n being constituted by hydrogen atoms; n is from 2 to 50.

2. Process for the preparation of ethylene-butadiene copolymcrs according to claim I, wherein the reaction is carried out at a molar ratio between the aluminum 10 compound containing AIN bonds and the vanadium compound higher fhan 0. l.

3. Process for the preparation of ethylene-butadiene copolymcrs according to claim I, wherein the reaction is carried out at a molar ratio between the aluminum alkyl-halide and the vanadium compound higher than 0.5.

4. Process for the preparation of ethylene butadiene eopolymers according to claim I, wherein the aluminum-triamide is aluminum trisdialkyl amide.

5. Process for the preparation of ethylene-butadiene copolymcrs according to claim I, wherein the reaction is carried out at a temperature in the range from 30 to +l 50C.

6. Process for the preparation of ethylcne-butadiene copolymcrs according to claim I, wherein the reaction is carried out at a total pressure in the range from I to I50 Kg/cm 7. Process for the preparation of ethylene-butadiene copolymcrs according to claim I, wherein the reaction is carried out in the presence ofa solvent selected from the group consisting of aliphatic aromatic and alicyclic hydrocarbons.

UNITED STATES PATENT AND TRADEMARK OFFICE CERTIFICATE OF CORRECTION PATENT NO. 3 901 2 DATED August 26, 197 NVENTOHSJi Salvatore Cucinella ani Alessandro Mazzei Hiscmflfiedmatmmrammaminweamwe-memfimdpahntmdflmtsmdLeflmsPawm mehembyconededasshownbmow:

Table 1, Column 2 under heading "Reaction vessel,

Autoclave", "ht. 2" should read -lt. 2--

Table 1, Column 8 sub-heading "Type" (under Cocatalyst"),

last entry "AlEtCl should read --AlEt Cl--.

Signed and Scaled this eleventh Of May 1976 [SEAL] A nest.

RUTH C. MASON Am'srmg ()jflcer C. MARSHALL DANN (mnmissimn-r nj'lurems and Trmlcmurkx 

1. PROCESS FOR THE PREPARATION OF ETHYLENE-BUTADIENE COPOLYMERS CONTAINING FROM 0.1 TO 95% BY MOLES OF BUTADIENE UNITS, WHEREIN THE POLYMERIZATION REACTION IS CARRIED OUT IN THE PRESENCE OF A TERNARY CATALYST SYSTEM CONSISTING ESSENTIALLY OF A VANADIUM OR VANADYL CHLORIDE B. AN ALUMINUM COMPOUND REPRESENTED BY THE FORMULA AIRXX3-X WHEREIN R IS ALKY L, ARYL, ALICYCLIC OR HYDROGEN, X IS A HALOGEN AND 1 $ X $ 2, AND C. AN ALUMINUM COMPOUND CONTAINING ALUMINUM-NITROGEN BONDS SELECTED FROM THE GROUPS CONSISTING OF: ALUMINUM TRIAMIDES HAVING THE GENERAL FORMULA A1(NR2)3 WHEREIN R HAS THE AFORSAID MEANING: A1HX(NR2)3-X WHEREIN R AND X HAVE THE AFORSAID MEANINGS: ALUMINUM POLYMERIC COMPOUNDS HAAVING THE FORMULA
 2. Process for the preparation of ethylene-butadiene copolymers according to claim 1, wherein the reaction is carried out at a molar ratio between the aluminum compound containing Al-N bonds and the vanadium compound higher than 0.1.
 3. Process for the preparation of ethylene-butadiene copolymers according to claim 1, wherein the reaction is carried out at a molar ratio between the aluminum alkyl-halide and the vanadium compound higher than 0.5.
 4. Process for the preparation of ethylene butadiene copolymers according to claim 1, wherein the aluminum-triamide is aluminum trisdialkyl amide.
 5. Process for the preparation of ethylene-butadiene copolymers according to claim 1, wherein the reaction is carried out at a temperature in the range from -30* to +150*C.
 6. Process for the preparation of ethylene-butadiene copolymers according to claim 1, wherein the reaction is carried out at a total pressure in the range from 1 to 150 Kg/cm2.
 7. Process for the preparation of ethylene-butadiene copolymers according to claim 1, wherein the reaction is carried out in the presence of a solvent selected from the group consisting of aliphatic, aromatic and alicyclic hydrocarbons. 